When designing an aircraft, projectile firing weapons systems are typically mounted internally in the aircraft. For example, the projectile firing weapons systems are typically mounted longitudinally (e.g., parallel to a roll axis of the aircraft) and fire projectiles through a fixed cowling or fairing of the aircraft. Some projectile firing weapons systems are fixedly coupled to the aircraft with a barrel that protrudes from a side of the fuselage. Operating the aircraft with a protruding barrel can negatively affect performance. For example, the protruding barrel may increase drag and reduce performance, such as endurance, speed, etc. As another example, an opening through which the barrel protrudes may cause wind buffeting which increases drag and stress on structures or an airframe of the aircraft.
When retrofitting an existing aircraft to include a projectile firing weapons system, the configurations described above may be hindered due to existing equipment or space constraints. In some implementations, a retrofit weapons system may be attached to an external structure (e.g., a hardpoint) of the aircraft. For example, a fixed (e.g., non-extendable or retractable) gun pod may be coupled to an external hardpoint on a wing or the fuselage of the aircraft. However, attaching a retrofit weapons system to an aircraft's exterior may interfere with airflow over the aircraft's surfaces (e.g., decreases lift and increases drag), which negatively affects aircraft performance (e.g., speed, maneuverability, operating ceiling, mission length, etc.).